Tag: Ultraviolet

How did supermassive black holes form in the early epochs of the universe? More importantly, how did they have enough time to grow as large as they did? The answer requires a very different universe. And back then, conditions were much different than they are now. There was a lot of gas, little dust, no stars, and a plethora of dark matter. Astronomers have spent decades observing early quasars, massive active galaxies powered by huge black holes feeding on surrounding gas. But these galaxies are seen so early in the universe’s history, one starts to wonder how a black hole finds sufficient...

Dark matter could be almost anything. With little data other than how much total dark matter mass exists, we can’t decode much about what individual chunks of dark matter might be made of. I’ve talked before about Massive Compact Halo Objects (MACHOs) and Weakly Interacting Massive Particles (WIMPs), but these are just two possibilities. Other theorists have talked about Modified Newtonian Gravity (MNG), where gravity may work differently on the grand scale than it does on our small Earth scales. Or perhaps it’s something I haven’t seen before. Maybe what we call dark matter is just a large population of ancient black holes....

I love false-colour images. They reveal detail that you can’t see in real life, but they also highlight things in an artistic way. For me it’s an excellent marriage of art and science, and as a communicator it helps me get concepts across in an accessible way. So when I saw the APOD image of Saturn from earlier this week, I had to discuss it. Saturn never has looked this way, and it never will. The colours are vivid and unrealistic, but they show the differences in three distinct but close wavelengths of light on the electromagnetic spectrum. All of...

The Past: Mars has water, and it used to have a lot more. If modern Mars had the ocean it once had, it would evaporate off into space quickly because there is no heavy atmosphere to help keep it pressurized and in liquid form. Mars would have had a thicker atmosphere in addition to it’s magnetic field in order to keep all that water in one place. So where did the atmosphere go? And if there was such a thick atmosphere, how does it account for the fingerprint of excess Carbon-13 and a lack of Carbon-12 found on the red planet...

We know that Mars lost an ocean of water, but what was the exact mechanism? We also know that the magnetic field of Mars was lost a long time ago, and contributed to this major loss of water and atmosphere. In a press conference today, NASA officials working with data from the Mars Atmosphere and Volatile Evolution (MAVEN) spacecraft, have shown that major solar storms have increased the amount of atmosphere and water loss over time. “Mars appears to have had a thick atmosphere warm enough to support liquid water which is a key ingredient and medium for life as...

Type 1a supernova explosions are used by Astronomers as a standard candle for measuring distances in Astronomy. They all explode with the same intrinsic brightness, and so depending on their apparent magnitude, ie how bright they look, we can determine the distance to them. It’s like a 40 watt light bulb. No matter how far away I move it, it’s still 40 watts, even though it looks dimmer if it’s further away. However, a few months ago some research came forward about type 1a supernova explosions, hinting that there may actually be two or more distinct types with slightly different...

Looking at the universe in different parts of the electromagnetic spectrum can reveal features and structures that are invisible to human eyes. The vast black emptiness of space explodes into a sea of colour when we use cameras to expand our vision. Looking at a galaxy through human eyes can be a simple and seemingly uninteresting view, but in infrared, microwave, or ultraviolet wavelengths we see the deeper layers of the vast array of stars. The closest large spiral galaxy and a cousin of our own Milky Way, the Andromeda galaxy, is revealed in ultraviolet. The Galaxy Evolution Explorer (GALEX)...

The Sun, stars, nebulae, galaxies, planets; We can see them all from our lonely cosmic address, but not all is revealed in the light our eyes see. We need to look at the entire electromagnetic spectrum to understand the range of objects we see in the universe. Our closest star shows us how different it can look when you change the observed wavelength. In high energy ultraviolet and X-ray light we can see the most powerful sunspots emitting their bursts of radiation and the swirls of solar plasma releasing ultraviolet energy in all directions. We still have a few years...

If there’s one true fact about every single gas giant planet ever observed, around the Sun or other stars in the Galaxy, it’s that they all are mainly composed of Hydrogen. Even though the giants of our solar system such as Neptune and Jupiter seem very different, it is Hydrogen that primarily composes them. The difference is in the details though. The blue colour of Neptune is due to the presence of Methane, and even then it only makes up 1.7% of Neptune’s mass. But Hydrogen is light. Wouldn’t giant planets like hot Jupiters lose their Hydrogen from being blasted...